This invention relates to means for securing a control line or lines to the exterior of a pipe, typically a control line protector for an oil well tubing string.
A typical producing oil well has a tubing string running inside a metal lined hole. Most producing wells have control valves installed in the tubing down hole. These valves, which may be hydraulically or electrically operated, require control lines to be run from the surface down the well alongside the tubing string. Also, control lines (including control cables) for submersible pumps have to be run similarly from the surface, and may be round or rectangular. Most tubing used for down hole completion is jointed approximately every 10 to 12 meters, the joints resulting in a local increase in diameter of the tubing string. Since the metal lined hole within which the tubing string runs is normally of constant diameter, there is accordingly a constriction of the annular space between the tubing string and the hole in the region of each joint.
A control line running the length of the tubing string externally thereof requires protection against being trapped between the joints and the inside of the hole, especially when lowering or pulling the tubing string in the well, and also requires attachment to the tubing string at intervals to prevent excessive slackness and to provide local support for the weight of the control line.
The known control line protectors suffer from various disadvantages. A typical prior art control line protector comprises a rigid steel casing consisting of two identical halves which are hinged together ready for assembly over the tubing string. Locking caps on one of the half members are deformed in engagement with the other member to secure the protector in position. The inner surface of one or both of the halves is formed with a channel or groove through which the control line or lines are led. No means is provided for adjusting the clamping pressure, and after a period of time the protector may loosen on the tubing string. Should this occur there is a danger that the protector may rotate on the tubing string such that the control lines may become trapped between the protector and a joint leading to the control lines being damaged or even severed.